Thermoplastic polymer having shape memory properties with high switching temperature, shaped polymer part produced therefrom and method for producing same

Abstract

A thermoplastic shape-memory polymer is proposed, comprising, on the one hand, hard segments with polyurethane units or with polyurea units obtained by polyaddition of the isocyanate groups of a diisocyanate with the hydroxyl groups or with the amino groups of a di-, tri-, or polyol or di-, tri-, and / or polyamine serving as a chain extender, and, on the other hand, soft segments containing polyether units or polycarbonate units, each of which is linked to the hard segments by forming urethane groups. The invention provides that the proportion of hard segments of the thermoplastic shape-memory polymer is at least 50% by weight, wherein at least one di-, tri-, and / or polyol or di-, tri-, and / or polyamine serving as a chain extender in the hard segments is formed from a cyclic, heterocyclic, or aromatic compound.The switching temperature of such a thermoplastic polymer with shape memory properties is at least 90°C, and it particularly exhibits a thermal resistance of at least 200°C. The invention further relates to a polymer molded part made of such a shape memory polymer and to a method for its production.

Description

[0001] The invention relates to a thermoplastic polymer with shape memory properties, comprising: (a) Hard segments containing polyurethane units obtained by polyaddition of the isocyanate groups of at least one diisocyanate with the hydroxyl groups of at least one di-, tri- and / or polyol serving as a chain extender to form urethane groups, and / or containing polyurea units obtained by polyaddition of the isocyanate groups of at least one diisocyanate with the amino groups of at least one di-, tri- and / or polyamine serving as a chain extender to form urea derivative groups;(b) Soft segments containing polyether units, wherein the polyether units are linked to the hard segments by polyaddition of corresponding polyether diols, triols and / or polyols to the isocyanate groups of the at least one diisocyanate of the hard segments to form urethane groups, and / or containing polycarbonate units, wherein the polycarbonate units are linked to the isocyanate groups of the hard segments by polyaddition of corresponding polycarbonate diols to form urethane groups.

[0002] The invention further relates to a polymer molded part which contains at least one thermoplastic polymer with shape memory properties of the aforementioned type or a polymer blend with at least one such polymer or is entirely formed therefrom, and to a method for producing such a polymer molded part in which the at least one thermoplastic polymer with shape memory properties is plasticized in a plasticizing unit and formed into the polymer molded part in at least one and / or following at least one outlet nozzle of the plasticizing unit.

[0003] Shape-memory polymers are polymers that typically consist of at least two polymer components or can also consist of a single polymer component with various segments. These segments include, on the one hand, so-called hard segments, which also function as lattice points. On the other hand, there are so-called soft segments, which connect the lattice points and are also referred to as switching segments. The soft or switching segments are softened or elastic at elevated temperatures (in which case they exist in an amorphous form), while they are rigid at lower temperatures (in which case they exist in a semi-crystalline or vitrified form).Such polymers can be programmed with regard to their shape by heating them to a temperature that corresponds at least to the so-called switching temperature, at which the phase transition (glass transition or melting transition) of the soft or switching segments takes place. At such a temperature, the polymer is then deformed, after which it is cooled to its so-called shape-fixing temperature, which corresponds to the crystallization temperature or glass transition temperature of the soft or switching segments and can be in the range of the switching temperature, but is usually lower. The soft or switching segments are then again in a semi-crystalline or vitrified form, so that the shape is retained. However, this shape is only temporary insofar as if such a mechanically deformed shape-memory polymer, "programmed" in this way, is heated to a specific temperature, namely its switching temperature, the soft or switching segments will revert to their original state.Switching segments are returned to their amorphous form, so that they can no longer counteract the restoring force induced by the hard component (lattice points) and the shape memory polymer returns to its original shape; the mechanical deformation is thus "reversed". Furthermore, some shape memory polymers can also be programmed by cold forming, in which the polymers are deformed at a temperature below their switching temperature, e.g., at ambient temperature, and, if the shape fixing temperature is lower, are cooled to their shape fixing temperature.In this case, too, only temporary deformation takes place, insofar as a re-deformation occurs upon renewed heating, at least to the switching temperature, in order to transfer the soft segments (switching segments) into the amorphous phase and thereby relax the mechanical stresses induced during cold deformation.

[0004] In addition to shape memory, thermoresponsive polymers can also exhibit temperature memory. This means that when the shape memory effect is triggered, the shape recovery begins at approximately the temperature at which the mechanical deformation was previously introduced into the material. Polymers with semicrystalline network structures, such as thermoplastic polyurethane elastomers, exhibit this type of material behavior (N. Fritzsche, T. Pretsch in Macromolecules 47, 2014, 5952-5959; N. Mirtschin, T. Pretsch in RSC Advances 5, 2015, 46307-46315).

[0005] One area of ​​application for such polymers with shape memory properties and / or thermoresponsive properties is, for example, various medical applications including bandages, compresses, insoles and the like, but also in everyday objects such as dishes, toys, pacifiers, textiles, mattresses, hoses, spindles, information carriers with tamper-proof markings (see, for example, DE 10 2015 014 291 B4) and the like.

[0006] A disadvantage of most currently known thermoplastic shape memory polymers based on polyurethane or polyurea is that their switching temperatures above approximately 50°C are very limited, and their shape-fixing temperature is typically lower. This restricts the potential applications of shape memory polymers, severely limiting their use and, in particular, their switching capabilities at higher ambient or process temperatures. For example, polycaprolactone-based thermoplastic polyurethanes with a melt transition temperature of the soft segments of up to approximately 55°C are known (B. Bogdanov, V. Toncheva, E. Schacht, L. Finelli, B. Sarti, M. Scandola: "Physical properties of poly(ester-urethane) prepared from different molar mass polycaprolactone-diols", Polymer 40, 1999, 3171-3182; J. Kloss, M. Munaro, GP De Souza, JV Gulmine, SH Wang, S. Zawadzki, L.Akcelrud: "Poly(ester urethane)s with polycaprolactone soft segments: a morphological study", J. Polym. Sci. Part A: Polym. Chem. 40, 2002, 4117-4130), which represent one of the few thermoplastic polyurethanes with shape memory properties and a switching temperature significantly higher than room temperature. If the polycaprolactone diol has an unusually high molar mass for the synthesis of thermoplastic polyurethanes, which can lead to coupling problems and an unclean reaction, and a low hard segment content, the melting point peak in the DSC thermogram (differential scanning calorimetry, DSC) can be brought close to that of the starting diol at 62°C (MW = 7000 g / mol and HSC = 18.7% in F. Li, L. Qi, J. Yang, M. Xu, X. Luo and D. Ma, J. Appl. Polym. Sci. 75, 2000, 68).For pure polycaprolactone with a molecular weight of 2000 g / mol, signals with respective peaks at 56°C and 63°C appear in the DSC thermogram during the melting transition upon heating. However, during subsequent cooling, the crystallization of the polycaprolactone takes place at very low temperatures below room temperature, with a peak at 17°C (J. Kloss, M. Munaro, GP De Souza, JV Gulmine, SH Wang, S. Zawadzki, L. Akcelrud, J. Polym. Sci. Part A: Polym. Chem. 40, 2002, 4117-4130).

[0007] Furthermore, polyether polyurethanes based on polytetramethylene glycol (PTMG) are known to exhibit a melting peak in the DSC thermogram at approximately 73°C and a crystallization peak at approximately 28°C (JD Merline, CP Nair, C. Gouri, GG Bandyopadhyay, KN Ninan, J. Appl. Polym. Sci. 107, 2008, 4082-4092). Other shape-memory polymers with similarly high switching and shape-fixing temperatures are found only in the class of predominantly amorphous materials. However, in these materials, any increase in switching temperature is always accompanied by a higher degree of cross-linking, leading to poorer thermal processability and even thermoset-like material behavior.

[0008] DE 10 2018 007 028 A1 describes a thermoplastic polyester polyurethane with shape memory properties, which on the one hand The product comprises hard segments containing polyurethane units obtained by polyaddition of the isocyanate groups of a diisocyanate with the hydroxy groups of a first diol serving as a chain extender to form urethane groups, and, on the other hand, crystallizable soft segments containing polyester units, wherein the polyester units are linked to the hard segments by polyaddition of corresponding polyester diols with the isocyanate groups of the diisocyanate to form urethane groups, and wherein the polyester diols are obtained by polycondensation of the hydroxy groups of a second diol with a dicarboxylic acid or with its derivatives to form ester groups.The polyester diols of the polyester units in the soft segments have an average molar mass between approximately 1500 g / mol and 10000 g / mol, with the switching temperature of the known thermoplastic polyester polyurethane with shape memory properties being at least 50°C, corresponding to the melting temperature of the soft segments, and the shape fixing temperature corresponding to the crystallization temperature of the soft segments being at least 20°C. The known shape memory polymer in the form of a polyester polyurethane thus possesses a comparatively high switching temperature, which opens up a range of previously untapped applications. However, due to its high proportion of polyester units, the shape memory polyester polyurethane exhibits a certain sensitivity to hydrolysis, which makes its use, for example, under ambient conditions with exposure to (atmospheric) humidity difficult.Furthermore, polyester polyurethanes with a very high polyester content have lower abrasion resistance compared to, for example, polyether polyurethanes, and tend to generate more dynamic heat under sustained mechanical stress. Regarding the switching factors for triggering the shape memory effect of known shape memory polymers, such as polyester polyurethanes with a (very) high polyester content in the soft segments, these are generally less pronounced than, for example, in polyether polyurethanes.

[0009] While thermoplastic polymers with shape memory properties can largely be processed into polymer molded parts using conventional thermoplastic processing methods such as extrusion, injection molding, hot pressing, etc., whereby they are plasticized in a plasticizing unit similar to an extruder and extruded from the plasticizing unit by means of an exit nozzle or nozzle assembly, some thermoplastic polymers with shape memory properties can also be processed using the fused deposition modeling process, as is used particularly in 3D printers.This fused deposition modeling (FDM) or fused filament fabrication (FFF) process is a manufacturing method in which one or more filaments made of thermoplastic polymer or a polymer blend of thermoplastic polymers are plasticized in a plasticizing unit of the 3D printer and deposited layer by layer through an exit nozzle typically located in the print head of the 3D printer. This process creates the polymer part, which is ultimately formed from a multitude of such layers or "droplets." This enables the layer-by-layer production of relatively complex parts, which is suitable for prototyping or small-batch production and cannot be replicated using conventional thermoplastic processing methods such as injection molding, extrusion, etc., molded parts that are difficult or impossible to manufacture, while the fused deposition modeling (FDM) process is increasingly used for the mass production of polymer molded parts with relatively complex geometries and / or surface structures. In the FDM process, also known as "additive manufacturing" 3D printing, a three-dimensional model of the molded part to be produced is typically created digitally, which can be done using well-known computer-aided design (CAD) methods. Furthermore, suitable software, such as a slicer program (e.g., ...), is used to create the model. CuraThe three-dimensional model of the polymer molded part to be produced (™< or similar) is decomposed into a plurality of thin layers. The plasticized polymer is then deposited layer by layer from the nozzle of the correspondingly moving printhead to build up the polymer molded part. Immediately after the polymer plastic, which is dispensed from the printhead nozzle in a more or less strand- or droplet-like form, is extruded, the curing process—or more precisely, the solidification process—begins. The deposited plastic solidifies, for example, at ambient temperature or under active cooling. A method for producing thermoplastic polymer molded parts with shape memory properties using the fused deposition modeling (FDM) process with 3D printers is known, for example, from DE 10 2018 003 273 A1.

[0010] The invention is based on the objective of proposing a relatively simple and cost-effective thermoplastic polymer with shape memory properties and hard segments based on polyurethane and / or polyurea of ​​the type mentioned above, which, while at least largely avoiding the aforementioned disadvantages and ensuring high shape recovery, has a higher switching temperature than the prior art in order to open up a wider field of application.It is further directed towards a polymer molded part which contains such a thermoplastic polymer with shape memory properties or is substantially entirely formed from such a polymer, and towards a method for producing such a polymer molded part in which the at least one thermoplastic polymer with shape memory properties is plasticized in a plasticizing unit and formed into the polymer molded part in at least one and / or following at least one exit nozzle of the plasticizing unit.

[0011] The first part of this problem is solved according to the invention in a thermoplastic polymer with shape memory properties of the type mentioned at the outset by the fact that the proportion of hard segments of the thermoplastic polymer with shape memory properties is at least 50 wt.%, and that at least one serving as a chain extender Di-, tri- and / or polyol and / or di-, tri- and / or polyamine the hard segments are formed from a cyclic, heterocyclic and / or aromatic compound, and that the switching temperature of the thermoplastic polymer with shape memory properties is at least 90°C.

[0012] To solve this problem, the invention further provides a polymer molded part which contains at least one thermoplastic polymer with shape memory properties of the aforementioned type or a polymer blend with at least one such polymer, or is essentially entirely formed from such a polymer, wherein the switching temperature of the at least one thermoplastic polymer with shape memory properties is at least 90°C.

[0013] In terms of process engineering, the invention provides for solving this problem in a method for producing such a polymer molded part, in that the at least one thermoplastic polymer with shape memory properties is heated in both the plasticizing unit and in the at least one outlet nozzle to a maximum temperature below the upper limit temperature of the melting transition temperature range of its hard segments, so that the hard segments are not completely melted, after which the at least one plasticized thermoplastic polymer with shape memory properties is dispensed from the at least one outlet nozzle of the plasticizing unit, formed into the polymer molded part and cooled to a temperature below the switching temperature in order to program the at least one thermoplastic polymer with shape memory properties together with the production of the polymer molded part in a temporary mold state.

[0014] The thermoplastic polymer according to the invention, possessing shape memory properties as well as thermoresponsive properties, therefore comprises, on the one hand, rigid segments based on polyurethane and / or on polyurea. In the former case, the rigid segments contain polyurethane units obtained by polyaddition of the isocyanate groups (-N=C=O groups) of at least one diisocyanate with the hydroxyl groups (-OH groups) of at least one di-, tri-, and / or polyol serving as a chain extender, forming urethane groups (-NH-CO-O-): RN=C=O + HO-R' ---> R-NH-CO-OR'

[0015] In the latter case, the hard segments contain polyurea units, which were obtained by polyaddition of the isocyanate groups of at least one diisocyanate (-N=C=O groups) with the amino groups (-NH₂ groups) of at least one di-, tri- and / or polyamine serving as a chain extender, forming urea derivative groups (-NH-CO-NH-): RN=C=O + H₂NR' ---> R-NH-CO-NH-R'

[0016] The thermoplastic polymer according to the invention, which has shape memory properties, further comprises soft or switching segments based on polyether and / or polycarbonate. In the former case, the soft segments contain polyether units, wherein the polyether units are linked to the hard segments by polyaddition of corresponding polyether diols, triols, and / or polyols with the isocyanate groups of the at least one diisocyanate of the hard segments, forming urethane groups. In the latter case, the soft segments contain polycarbonate units, wherein the polycarbonate units are linked to the isocyanate groups of the hard segments by polyaddition of corresponding polycarbonate diols, forming urethane groups.

[0017] Furthermore, it is of course also conceivable that the thermoplastic polymer according to the invention with shape memory properties contains additional soft or switching segments, such as polyester units known from the aforementioned DE 10 2018 007 028 A1, which are linked to the hard segments by polyaddition of corresponding polyester diols, triols and / or polyols with the isocyanate groups of the at least one diisocyanate of the hard segments, forming urethane groups. Such polyester diols can be formed, for example, by reaction of the hydroxy groups of a diol with a dicarboxylic acid or with its derivatives, such as, for example,of the corresponding diacid halides, diesters, cyclic anhydrides or the like, forming ester groups (-CO-O-), examples of such polyester units include polyalkylene terephthalate units, in particular polyethylene (PET), polypropylene (PPT) and / or polybutylene terephthalate (PBT) units, and / or polyalkylene furanoate units, in particular polyethylene furanoate (PEF) units.

[0018] Surprisingly, it was found that such a thermoplastic polymer can be given very high switching temperatures of at least, and especially above, about 90°C, and particularly up to about 150°C, if the thermoplastic polymer with shape memory properties has a high proportion of hard segments of at least about 50 wt%, based on the mass of the entire molecule, and at least one di-, tri-, and / or polyol and / or di-, tri-, and / or polyamine of the hard segments, serving as a chain extender, is formed from a cyclic, heterocyclic, and / or aromatic compound. While diols or diamines can usually be used here, alcohols or amines with more than two hydroxy or amino groups can also be used additionally or alternatively, with slight branching of the hard segments, which, for example,The proportion of multifunctional starting materials can be controlled without impairing the thermoplastic properties of the polymer. Furthermore, the polymer according to the invention, with shape memory properties, exhibits high temperature stability well above 200°C and, according to its usual programming—by heating it to its switching temperature, mechanically deforming it into a temporary shape, and cooling it while maintaining the temporary shape at least to its shape-fixing temperature—develops high restoring forces when the polymer is returned to its original or permanent shape by triggering the shape memory effect by heating the polymer to its switching temperature.

[0019] In this way, new technical applications are opened up for the thermoplastic shape memory polymer according to the invention, such as in the field of fire protection (e.g., for thermal actuators for smoke dampers, fire doors, unlocking mechanisms, etc.), in the field of aerospace, and also in vehicle engineering, including the automotive sector. Here, the thermoplastic shape memory polymer according to the invention can be used in thermal actuators, for example, as well as in thermoresponsive unfolding and folding mechanisms. Furthermore, ultra-hard polymer molded parts, such as those that can be manufactured from the shape memory polymer according to the invention, offer particular technical advantages in medical technology, for example, as implant or bone replacement materials. The processing of the thermoplastic polymer with shape memory properties, which, for example,The polymer can be used as granules or in powder form, and the desired polymer molded parts can be produced, for example, by means of known thermoplastic processing methods such as injection molding, extrusion, hot pressing, sintering or the like.

[0020] Furthermore, any known additives can of course be added to the thermoplastic shape memory polymer according to the invention, such as lubricants, plasticizers, antioxidants, UV stabilizers, reinforcing agents, e.g. in fiber form, flame retardants, antistatic agents, hydrolysis stabilizers, impact modifiers, biostatic agents, etc., or fillers that absorb electromagnetic radiation, heat radiation, etc., thermally and / or electrically conductive fillers, for example in the form of metal or carbon particles of various carbon modifications, in order to, for example, selectively influence the switching behavior of the shape memory polymer by external influences such as electromagnetic radiation, heat, etc.

[0021] To ensure a very high switching temperature combined with very high thermal resistance, an advantageous embodiment may provide that the thermoplastic polymer according to the invention, which has shape memory properties, has a proportion of hard segments of at least approximately 60% by mass, in particular at least approximately 70% by mass, preferably at least approximately 80% by mass, and most preferably at least approximately 85% by mass. On the other hand, the proportion of hard segments should preferably be at most approximately 98.5% by mass, in particular at most approximately 97.5% by mass, and more preferably at most approximately 96.5% by mass, so that the thermoplastic polymer according to the invention has pronounced shape memory properties.

[0022] Regarding the chain extenders of the hard segments according to the invention in the form of cyclic, heterocyclic and / or aromatic compounds, which are presumed to be able to lead to the high switching temperatures due to steric effects in conjunction with a high proportion of hard segments in the molecule, in the case of at least one di-, tri- and / or polyol of the hard segments serving as a chain extender, it may be advantageously provided that it is from the group consisting of dianhydrohexitols, in particular from the group consisting of isosorbide (1,4:3,6-dianhydro-D-sorbitol), isomannide (1,4:3,6-dianhydro-D-mannitol) and isoidide (1,4:3,6-dianhydro-L-iditol). of dihydroxybenzenes, such as 1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol) and 1,4-dihydroxybenzene (hydroquinone), of trihydroxybenzenes, such as 1,3,5-trihydroxybenzene (phloroglucinol), 1,2,4-trihydroxybenzene (hydroxyhydroquinone) and 1,2,3-trihydrobenzene (pyrogallol), of aliphatic cyclic diols, in particular with at least one C5 and / or C6 ring, preferably from the group consisting of cis-1,2-cyclohexanediol, trans-1,2-cyclohexanediol, cis-1,3-cyclohexanediol, trans-1,3-cyclohexanediol, cis-1,4-cyclohexanediol, trans-1,4-cyclohexanediol, cis-1,2-cyclopentanediol, trans-1,2-cyclopentanediol, cis-1,3-cyclopentanediol, trans-1,3-cyclopentanediol and 1,3-cyclopent-4-enediol, the tetrahydrofuran-based heterocyclic diols, in particular tetrahydrofuran-2,5-dimethanol and tetrahydrofuran-2,5-diethanol, the di- and trihydroxybenzoic acids, in particular 3,4,5-trihydroxybenzoic acid (gallic acid), the aromatic di-, tri- and polyols with at least 2 benzene rings, in particular 3,3',4',5,7-Pentahydroxyflavone (quercetin), polyphenols with at least two hydroxy groups, in particular trans-3,5,4'-trihydroxystilbene (resveratrol), catechins with at least two hydroxy groups, and alkylamine- or alkanolamine-substituted dihydroxybenzenes, in particular from the group consisting of 4-(2-aminoethyl)benzene-1,2-diol (dopamine) and (R)-3,4-dihydroxyphenylethanolamine (noradrenaline), including mixtures thereof.

[0023] In the case of at least one di-, tri- and / or polyamine serving as a chain extender in the hard segments, it may be advantageously provided that it is selected from the group of the diaminobenzenes, such as 1,2-diaminobenzene (o-phenylenediamine), 1,3-diaminobenzene (m-phenylenediamine) and 1,4-diaminobenzene (m-phenylenediamine), of the triaminobenzenes, such as 1,3,5-triaminobenzene, 1,2,4-triaminobenzene and 1,2,3-triaminobenzene, of the aliphatic cyclic diamines, in particular with at least one C 5 and / or C 6 ring, preferably from the group consisting of 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 2,4-diaminocyclohexane, 2,6-diamino-1-methylcyclohexane, 1,3-diaminomethylcyclohexane, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 4,4'-diaminodicyclohexylmethane, 3,3"-Dimethyl-4,4'-diaminodicyclohexylmethane and 3-Aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), the tetrahydrofuran-based heterocyclic diamines, in particular 2,5-furandimethanamine (2,5-bis(aminomethyl)furan), 2,5-furandiethanamine (2,5-bis(aminoethyl)furan) and [2-amino-1-(furan-2-yl)ethyl]dimethylamine, and the nitrogen-based heterocyclic diamine compounds,especially from the group porphyrin (porphine) and 7,8-dihydroporphyrin (chlorine), , including their mixtures.

[0024] Furthermore, it can be advantageous for various reasons if the hard segment diisocyanate is also formed from a cyclic, heterocyclic, and / or aromatic compound. Examples of particularly suitable hard segment diisocyanates include methylenediphenyl diisocyanates (MDI), especially from the group consisting of diphenylmethane-2,2'-diisocyanate (2,2'-MDI), diphenylmethane-2,4'-diisocyanate (2,4'-MDI), diphenylmethane-4,4'-diisocyanate (4,4'-MDI), including their isomers and mixtures thereof, isophorone diisocyanate (IPDI), 4,4'-diisocyanatodicyclohexylmethane (H12MDI), isomers or mixtures of toluene diisocyanates (TDI), or mixtures thereof.

[0025] With regard to the molar mass of the hard segments of the thermoplastic polymer with shape memory properties according to the invention, it can advantageously be provided that the hard segments have an average molar mass of at least about 550 g / mol, in particular at least about 750 g / mol, preferably at least 1000 g / mol, most preferably at least about 1250 g / mol. The entire molecule of the thermoplastic polymer with shape memory properties can preferably have an average molar mass of at least about 650 g / mol, in particular of at least about 1000 g / mol, preferably of at least about 2000 g / mol, most preferably of at least about 3000 g / mol, and / or of at most about 500000 g / mol, in particular of at most about 350000 g / mol, preferably of at most about 300000 g / mol, most preferably of at most about 200000 g / mol, exhibit.

[0026] As already mentioned, the soft segments of the thermoplastic polymer with shape memory properties according to the invention contain polyether units and / or polycarbonate units. In this context, it can advantageously be provided that the polyether units of the soft segments Polyalkylene glycol units, in particular from the group of polyethylene (PEG), polypropylene (PPG) and polybutylene glycol units (PBG), and / or polytetrahydrofuran (PTHF) units The polycarbonate units of the soft segments may, for example, contain polyalkylene carbonate units, such as poly(hexamethylene carbonate) units (PHC) or the like, which have been linked to the isocyanate groups of the hard segments by polyaddition of corresponding polycarbonate diols to form urethane groups.

[0027] The soft segments of the thermoplastic polymer with shape memory properties can preferably have a medium molar mass. of at least about 100 g / mol, in particular of at least about 150 g / mol, preferably of at least about 200 g / mol, e.g. of at least about 250 g / mol, and / or of at most about 10000 g / mol, in particular of at most about 5000 g / mol, preferably of at most about 4000 g / mol, e.g. of at most about 3000 g / mol, exhibit.

[0028] As already indicated, the invention makes it possible for the thermoplastic polymer with shape memory properties to have a switching temperature significantly above about 90°C, such as at least about 100°C, in particular at least about 110°C, preferably at least 120°C or at least about 130°C.

[0029] The thermal resistance of the thermoplastic polymer according to the invention with shape memory properties is preferably at least about 200°C, in particular at least about 220°C, preferably at least 240°C, or more.

[0030] The programming of the thermoplastic polymer with shape memory properties according to the invention into a temporary shape can, in principle, be carried out in a manner known as such, by, for example, thermomechanically treating a polymer molded part produced by any known thermoplastic processing method from such a shape memory polymer or from a polymer blend containing such a polymer after its actual production, in order to convert the thermoplastic polymer with shape memory properties into a desired temporary shape, from which it can then be converted back into its original - e.g. permanent - shape when the polymer molded part is heated to the switching temperature of the at least one thermoplastic polymer with shape memory.The thermomechanical treatment typically involves heating the thermoplastic polymer with shape memory properties at least to the range of its switching temperature in order to then deform it into the desired temporary shape, after which it is cooled again to a temperature below its switching temperature while maintaining the temporary shape.

[0031] However, such subsequent thermomechanical treatment can be relatively time-consuming, energy-intensive, and therefore costly, particularly in the case of thermoplastic polymers with shape memory properties according to the invention, which have a high switching temperature of at least 90°C. Therefore, the inventive method for producing a polymer molded part, which contains at least one thermoplastic polymer with shape memory properties according to the invention or a polymer blend with at least one such polymer, or is essentially entirely composed thereof, provides that the at least one thermoplastic polymer with shape memory properties is plasticized in a plasticizing unit and formed into the polymer molded part in at least one and / or downstream of at least one exit nozzle of the plasticizing unit.wherein the at least one thermoplastic polymer with shape memory properties is heated in both the plasticizing unit and the at least one outlet nozzle to a maximum temperature below the upper limit of the melting transition temperature range of its hard segments, so that the hard segments are not completely melted, after which the at least one plasticized thermoplastic polymer with shape memory properties is dispensed from the at least one outlet nozzle of the plasticizing unit, formed into the polymer molded part and cooled to a temperature below the switching temperature in order to program the at least one thermoplastic polymer with shape memory properties together with the production of the polymer molded part in a temporary mold state.

[0032] In this way, a shape memory effect can be imprinted on the polymer molded part simultaneously with its production – or more precisely: the polymer molded part can be produced in a temporary mold during production, from which it can then be subsequently transferred into a permanent mold, provided it is heated to the switching temperature of the at least one thermoplastic polymer with shape memory properties. The thermoplastic polymers with shape memory properties used according to the invention are therefore heated during their plasticization only to a maximum temperature below the upper limit of the melting transition temperature range of their hard segments, i.e., to a temperature at which at least the hard segments are not completely melted.In this state, the plasticized thermoplastic polymers with shape memory properties are dispensed from the at least one outlet nozzle of the plasticizing unit, formed into the polymer molded part, and cooled to a temperature below the switching temperature or below the glass transition temperature range. It was found that this makes it possible to program the at least one thermoplastic polymer with shape memory properties in a temporary mold state during the production of the polymer molded part; that is, it is brought into a temporary mold during its forming process, from which it can later be transferred into a permanent mold when the at least one thermoplastic polymer with shape memory properties is heated at least to, or expediently above, its switching temperature, but below the melting transition temperature range of its hard segments.Due to the incomplete melting of at least the hard segments, the physical lattice points of the thermoplastic polymer with shape memory properties are also not completely melted. Simultaneously, shear and tensile forces are introduced into the plasticized polymer material during the thermoplastic processing to form the polymer part. After exiting the plasticizing unit's die and cooling to a temperature below the switching temperature (i.e., below the glass transition temperature range of the soft segments), the deformations introduced into the polymer material as a result of these mechanical forces, such as strains, are fixed by the vitrification of the soft segments, which can also consist of mixed phases of soft and hard segments. This process imprints a shape memory effect, particularly a thermoresponsive one.The cooled polymer molded part then remains in its temporary shape, which was given to it during its manufacture by means of thermoplastic processing methods, until it is heated to a temperature above the glass transition temperature range or above the switching temperature, which is usually around the glass transition temperature range or can be slightly higher, whereupon it is transformed into its permanent shape without the application of mechanical forces.

[0033] The inventive method not only makes thermoplastic processing of the inventive thermoplastic polymers with shape memory properties possible using classic thermoplastic processing methods, e.g. using an extruder, whereby the resulting polymer molded part can simultaneously be given a shape memory effect, but is particularly suitable for use in the fused deposition modeling process using 3D printers (see also below).Another advantage, for example, is that the inventive method makes it possible in a relatively simple and economical way to provide for even very complex three-dimensional shape changes following the production of the polymer molded part by transferring it from its temporary shape, imparted during production, into its permanent shape, without the need for elaborate tools such as those used in the case of subsequent thermomechanical treatment to transfer a polymer molded part made of shape memory polymers from its permanent shape into a temporary shape.

[0034] Finally, it should be noted at this point that the inventive method also opens up the possibility, for example, of processing an inventive thermoplastic polymer with shape memory properties together with at least one further thermoplastic polymer with shape memory properties, either according to the invention or already known, which may have different switching or glass transition temperatures of their soft segments. In this way, it is possible, on the one hand, to selectively adjust the switching temperatures for the phase transitions of a polymer molded part produced in this way; on the other hand, alternatively or additionally, by means of a Be Influence of heat transport in different areas of the polymer molded part by time-dependent switching, dh eiA time-dependent, region-specific deformation of the polymer molded part from the manufacturing-induced temporary shape to the permanent shape can be triggered. For this purpose, for example, polymer blends or polymer mixtures with at least one thermoplastic polymer according to the invention with shape memory properties can be used, or, particularly when producing polymer molded parts using the fused deposition modeling process with 3D printers, several printing filaments made of different polymers can be used (so-called "multi-material printing"), wherein at least one or all of these polymers are thermoplastic polymers according to the invention with shape memory properties.

[0035] In an advantageous embodiment of the method according to the invention, it can be provided that the at least one thermoplastic polymer with shape memory properties is heated to a maximum temperature in both the plasticizing unit and the at least one exit nozzle, which corresponds at most to a temperature peak of the melt transition temperature range of its hard segments in a DSC thermogram obtained by means of differential scanning calometry (DSC) during heating, wherein the at least one thermoplastic polymer with shape memory properties is heated in both the plasticizing unit and the at least one exit nozzle, in particular to a maximum temperature below the lower limit temperature of the melt transition temperature range of its hard segments. erIf the hard segments of the thermoplastic polymer with shape memory properties are heated during processing only to a maximum of the lower limit temperature of the melting transition temperature range of the hard segments or only slightly above it, the hard segments are practically not or only slightly melted, thus retaining their network structure and primarily resulting only in a reorientation of the lattice points without phase change of the hard segments, which in turn enables the introduction of high residual stresses.

[0036] It was found that the stresses introduced into the polymer during the extrusion of the thermoplastic polymer with shape memory properties from the nozzle depend significantly on the set speed of the nozzle, such as on the print head of a 3D printer, with a higher degree of alignment of the polymer strands being achieved by moving the nozzle faster. In an advantageous embodiment, it can be provided that the at least one nozzle of the plasticizing unit is operated at a certain speed during the extrusion of the at least one plasticized thermoplastic polymer with shape memory properties. of at least about 1 mm / s, in particular of at least about 2 mm / s, e.g. of at least about 3 mm / s or of at least about 4 mm / s; preferably of at least 5 mm / s; and / or of at most about 80 mm / s, e.g. of at most about 70 mm / s, in particular of at most about 60 mm / s, such as of at most about 50 mm / s, preferably of at most about 40 mm / s, is being moved.

[0037] According to a further development of the inventive method, it can also be provided that the at least one thermoplastic polymer with shape memory properties is held and deformed at a temperature in the range of or above the switching temperature during and / or after its dispensing from the at least one outlet nozzle of the plasticizing unit, in order to additionally program it in a temporary shape state under the influence of mechanical forces or stresses, after which it is cooled to a temperature below the switching temperature. Such deformation in a (still) predominantly amorphous state of the soft segments can be carried out, for example, by means of suitable molding tools, by means of suitable molding nozzles used as outlet nozzles of the plasticizing unit, by means of calibration units downstream of the outlet nozzle to calibrate the plasticized strand, or on the, e.g.The printing process takes place on the print bed of a 3D printer, which is tempered to the respective temperature, whereby - as already mentioned - the print head and / or the print bed can be moved at different relative speeds to each other during the depositing of the plastic strands in order to introduce mechanical forces or stresses of the desired direction and amount into the polymer material and thereby control the shape recovery capacity.

[0038] As already mentioned, the programmed shape recovery capacity of the at least one thermoplastic polymer with shape memory properties can be changed by controlling various process parameters, wherein the programmed shape recovery capacity of the at least one thermoplastic polymer with shape memory properties is preferably changed by controlling at least one parameter from the group The temperature set in the plasticizing unit, the temperature of at least one outlet nozzle of the plasticizing unit (as already mentioned, the lower the temperature set in the plasticizing unit and / or in its outlet nozzle, i.e., the more incompletely or practically not at all the hard segments of the thermoplastic polymer have been melted during its processing into the polymer molded part, results in a qualitatively greater shape recovery capacity of the in situ programmed polymer molded part).the more "undercooled" the thermoplastic polymer with shape memory properties has been processed), speed of the at least one exit nozzle during the dispensing of the at least one thermoplastic polymer with shape memory properties (as already mentioned, the deposition rate can be used to control, in particular, the stresses introduced into the polymer and the orientation of the polymer strands), temperature gradient during the cooling of the at least one thermoplastic polymer with shape memory properties (the extent of the shape memory effect can be controlled by the cooling rate, whereby the highest possible cooling rates with a large temperature gradient and consequently a rapid "freezing" of the stresses introduced into the polymer lead to particularly pronounced re-deformations; the temperature gradient can be, for example,by means of external cooling devices and / or, in the case of 3D printing, by a correspondingly low temperature of the print bed), pressure set inside the plasticizing unit (meaning that mechanical forces of different magnitude and / or direction can be introduced into the not completely melted polymer material by means of a corresponding pressure), type and / or quantity of heat radiation absorbing and / or thermally conductive additives added to the at least one thermoplastic polymer with shape memory properties (by using such additives, for example in the form of coatings or, in particular, in the form of, preferably particulate, fillers, the cooling of the polymer strand ejected from the nozzle and thus the extent of the residual stresses introduced in the process can also be controlled), . is being discontinued.

[0039] As already indicated, an advantageous embodiment of the inventive method provides that the at least one thermoplastic polymer with shape memory properties is plasticized in a plasticizing unit of a 3D printer, dispensed from the plasticizing unit by means of at least one exit nozzle in the form of a print head of the 3D printer which is controlled to be relatively movable with respect to a print table or a print bed, and deposited layer by layer to form the polymer molded part, after which the plastic strands dispensed layer by layer by means of the exit nozzle(s) of the print head are cooled to a temperature below the switching temperature or below the glass transition temperature range of the soft segments.Thus, when producing the polymer molded part in its temporary form using such a fused deposition modeling (FDM) process, it is easily possible to adjust the direction of the desired return to the permanent shape of the polymer molded part by determining the deposit direction of the plastic strands on the build platform through appropriate relative movement of the print head with respect to the build platform. Likewise, it is possible to achieve different return directions for the same polymer molded part by creating different areas of the polymer molded part through varying relative movements of the print head with respect to the build platform; that is, the orientation of the layer-by-layer deposited plastic strands from which the polymer molded part is printed can be selected differently in different areas of the polymer molded part.As already mentioned, different recovery behaviors can also be achieved in one and the same polymer molded part by different relative speeds of the print head with respect to the print bed, in that different mechanical forces or stresses are introduced into the practically unmelted or at least not completely melted hard segments of the at least one polymer with shape memory properties, which are relaxed at least to the switching temperature during a subsequent heating in order to trigger the shape return to the permanent shape.If desired, the plastic strands of the at least one thermoplastic polymer with shape memory properties can also be kept at a temperature in or above the glass transition temperature range and (additionally) deformed during and / or after their ejection from the at least one print head of the 3D printer in order to additionally program them in a temporary shape state under the influence of mechanical forces or stresses, for example by controlling the direction and / or the magnitude of the relative speed of the print head with respect to the print bed.

[0040] The finished polymer molded part can be heated at virtually any time after its production according to the invention to a temperature at or above the switching temperature or the glass transition temperature range of the soft segments in order to transfer it from its programmed temporary molded state to a permanent molded state.

[0041] The invention is explained in more detail below with reference to exemplary embodiments and the drawings. These show: Fig. 1 a measurement curve of the mass as a function of temperature determined by thermogravimetric analysis of each embodiment of thermoplastic polymers with shape memory properties according to embodiments 1 and 2; Fig. 2 a measurement curve of temperature and restoring force as a function of time determined by dynamic-mechanical analysis for determining the restoring force when switching the embodiment of a thermoplastic shape memory polymer according to embodiment 1; Fig. 3 a measurement curve of the storage module determined by dynamic-mechanical analysis when heating the embodiment of a thermoplastic shape memory polymer according to embodiment 1 from -80°C to 160°C; Fig.4. A measurement curve of strain as a function of time at different temperatures, determined by means of dynamic-mechanical analysis, for characterizing the shape memory effect of the embodiment of a thermoplastic shape memory polymer according to the invention as defined in embodiment 1; Fig. 5. A graph of heat flow as a function of temperature, determined by means of differential scanning calorimetry (DSC), for determining the glass transition temperature of the embodiment of a thermoplastic shape memory polymer according to the invention as defined in embodiment 1; Fig. 6. A graph of the loss factor tan δ, determined by means of dynamic-mechanical analysis, which results from the ratio of loss and storage modulus and characterizes the damping behavior of a material, for determining the glass transition temperature of the embodiment of a thermoplastic shape memory polymer according to the invention as defined in embodiment 1; Fig.Fig. 7 A graph of the determined stress as a function of time when heating from 23°C to 140°C to characterize the restoring stress of a tensile bar stretched by 100% of the embodiment of a thermoplastic shape memory polymer according to the invention, as described in embodiment 2; Fig. 8 A graph of the heat flow as a function of temperature, determined by differential scanning calorimetry (DSC), to determine the glass transition temperature of the embodiment of a thermoplastic shape memory polymer according to the invention, as described in embodiment 2; Fig. 9 A graph of the loss factor tan δ, determined by dynamic mechanical analysis, which results from the ratio of loss and storage modulus and characterizes the damping behavior of a material, to determine the glass transition temperature of the embodiment of a thermoplastic shape memory polymer according to the invention, as described in embodiment 2; Fig.Fig. 10 a mass curve as a function of temperature determined by thermogravimetric analysis of an embodiment of a thermoplastic polymer with shape memory properties according to embodiment 3; Fig. 11 a heat flow graph as a function of temperature determined by differential scanning calorimetry (DSC) in a temperature range from about -60°C to about 160°C for determining the glass transition temperature of the embodiment of a thermoplastic shape memory polymer according to embodiment 3; Fig. 12 a heat flow graph as a function of temperature determined by differential scanning calorimetry (DSC) in a temperature range from about 0°C to about 270°C for determining the melt transition temperature range of the hard segments of the embodiment of a thermoplastic shape memory polymer according to embodiment 3; Fig.13 a diagram of the loss factor tan δ determined by means of dynamic-mechanical analysis, which results from the ratio of loss and storage modulus and characterizes the damping behavior of a material, for determining the glass transition temperature of the embodiment of a thermoplastic shape memory polymer according to the inventive model 3; Fig. 14 a diagram determined by means of dynamic-mechanical analysis . erAverage measurement curve of the strain as a function of time at different temperatures for characterizing the shape memory effect of the embodiment of a thermoplastic shape memory polymer according to the invention as described in embodiment 3; Fig. 15 shows a photographic view of a test specimen in the form of a rod printed from the shape memory polymer according to the invention as described in embodiment 3 and programmed in situ, both after printing (top) and after triggering the shape memory effect (bottom); and Fig. 16 shows a photographic view of a test specimen in the form of a ring printed from the shape memory polymer according to the invention as described in embodiment 3 and programmed in situ, both after printing (top) and after triggering the shape memory effect (bottom). Examples of implementation: Example 1:

[0042] Production of a thermoplastic polyether polyurethane with shape memory properties and thermoresponsive properties with a switching temperature in the range of 122°C to 125°C: Hard segments: Polyurethane units obtained by polyaddition of a diisocyanate in the form of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with a diol serving as a chain extender in the form of isosorbide (IS, 1,4:3,6-dianhydro-D-sorbitol); Soft segments: Polyether units in the form of polypropylene glycol (PPG) with a numerically average molar mass of approximately 430 g / mol.

[0043] The thermoplastic polyether polyurethane with shape memory properties is synthesized using the prepolymer process by reacting the reactants in a molar ratio of PPG : 4,4'-MDI : IS = 1 :4,7 :3,7, corresponding to a proportion of hard segments of 88.1 wt% and a proportion of soft segments of 11.9 wt%.

[0044] As can be seen from the Fig. 1 As shown in the thermogravimetric analysis results, the polyether polyurethane synthesized in the above manner exhibits shape memory properties and a thermal resistance of approximately 260°C. According to the DSC diagram, the Fig. 5The polyether polyurethane with shape memory properties possesses a glass transition temperature representative of its switching temperature in the range of approximately 122°C. This essentially corresponds to the tan 5 peak determined by dynamic mechanical analysis at a glass transition temperature of approximately 124.6°C (see the Fig. 6 ), where the loss factor tan δ results from the ratio of loss modulus to storage modulus.

[0045] Plate-shaped samples measuring 10 mm x 20 mm x 2 mm were produced from the shape-memory polyether polyurethane and temporarily bent into a 180° shape for programming. Restoring forces exceeding 3 N were observed upon heating to the switching temperature (see above) (cf. the force curve [N] determined by dynamic-mechanical analysis according to the...). Fig. 2It is assumed that these comparatively high restoring forces are due to a pronounced jump in the storage module (here: from 2.4 GPa at 23°C to less than 15 MPa at temperatures above 140°C; cf. the Fig. 3 ), which corresponds to a switching factor of approximately 160.

[0046] As can be seen from the Fig. 4 To investigate the thermomechanical properties of polyether polyurethane with shape memory properties, a test specimen produced from this material was repeatedly deformed using a programmed process. After each deformation, the shape memory effect was triggered by heating the specimen to the glass transition or switching temperature (see above) of the shape memory polymer. The specimen could be repeatedly deformed into a temporary shape with an elongation of at least 100%, after which it could be returned to its permanent shape by triggering the shape memory effect. Example 2:

[0047] Production of a thermoplastic polyurethane with shape memory properties and thermoresponsive properties with a switching temperature in the range of approximately 146°C to 147°C: Hard segments: Polyurethane units obtained by polyaddition of a diisocyanate in the form of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with a diol serving as a chain extender in the form of isosorbide (IS, 1,4:3,6-dianhydro-D-sorbitol); Soft segments: Poly(hexamethylene carbonate) units, which are linked by polyaddition of poly(hexamethylene carbonate)diol (PHC) to the isocyanate groups of the hard segments to form urethane groups, with a numerically average molar mass of about 1000 g / mol.

[0048] The thermoplastic polyurethane with shape memory properties is synthesized using the prepolymer process by reacting the reactants in a molar ratio of PHC : 4,4'-MDI : IS = 1 :10.5 :9.5, corresponding to a proportion of hard segments of 95 wt% or a proportion of soft segments of 5 wt%.

[0049] As can be seen from the Fig. 1 As can be seen from the thermogravimetric analysis results, the polyurethane synthesized in the above manner with shape memory properties, similar to that of Example 1 above, exhibits a thermal resistance of approximately 260°C. According to the DSC diagram, Fig. 8The polyurethane with shape memory properties possesses a glass transition temperature representative of its switching temperature in the range of approximately 147°C. This essentially corresponds to the tan δ-peak determined by dynamic-mechanical analysis at a glass transition or switching temperature of approximately 146.0°C (see the Fig. 9 ).

[0050] As from the Fig. 7 As can be seen, rod-shaped test specimens were produced from the thermoplastic shape memory polymer and deformed into a temporary shape at a programmed elongation of 100%. When heated to the switching temperature (see above) to trigger the shape memory effect and return to the permanent shape, a very high restoring stress of approximately 23.5 MPa was measured. Example 3:

[0051] Production of a thermoplastic polyurethane with shape memory properties and thermoresponsive properties with a switching temperature in the range of approximately 120°C to 121°C: Hard segments: Polyurethane units obtained by polyaddition of a diisocyanate in the form of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with a diol serving as a chain extender in the form of isosorbide (IS, 1,4:3,6-dianhydro-D-sorbitol); Soft segments: Poly(hexamethylene carbonate) units, which are linked by polyaddition of poly(hexamethylene carbonate)diol (PHC) to the isocyanate groups of the hard segments to form urethane groups, with a numerically average molar mass of about 500 g / mol.

[0052] The thermoplastic polyurethane with shape memory properties is synthesized using the prepolymer process, in which the reactants are reacted in a molar ratio of PHC : 4,4'-MDI : IS = 1 :3.35 :2.33, corresponding to a proportion of hard segments of about 70 wt% or a proportion of soft segments of about 30 wt%.

[0053] As can be seen from the Fig. 10 As can be seen from the results of a thermogravimetric analysis, the polyurethane with shape memory properties synthesized in the manner described above, according to Example 3, exhibits a thermal resistance of approximately 275°C. According to the DSC diagram, Fig. 11The polyurethane with shape memory properties possesses a glass transition temperature range representative of its switching temperature, in the range of approximately 95°C to approximately 125°C. This essentially corresponds to the tan δ-peak determined by dynamic-mechanical analysis at a glass transition or switching temperature of approximately 120.8°C (see the Fig. 13 ). From the DSC diagram according to Fig. 12 It is further evident that the melting transition temperature range of the hard segments is in the range of approximately 207.4°C to approximately 255°C, i.e., approximately 20°C to 65°C below its thermal resistance.

[0054] Again Fig. 13As can be seen, the thermomechanical properties of polycarbonate polyurethane with shape memory properties were investigated by repeatedly deforming a test specimen produced from it using a programmed process. After each deformation, the shape memory effect was triggered by heating the specimen to the glass transition or switching temperature (see above) of the shape memory polymer. The specimen could be repeatedly deformed into a temporary shape with an elongation of at least 100%, after which it could be returned to its permanent shape by triggering the shape memory effect. The shape retention in the second cycle was approximately 99%; the shape recovery in the second cycle was approximately 80%.

[0055] Furthermore, test specimens in the form of rods were produced from the thermoplastic polycarbonate polyurethane with shape memory properties according to Example 3 using a 3D printer (see the Fig. 15) as well as in the form of rings (see the Fig. 16 ) printed, each with a nozzle temperature of approximately 190°C, i.e., approximately 17°C below the lower limit of the melting transition temperature range of the hard segments of 207.4°C (see the Fig. 12 The print head speed relative to the print bed was set to approximately the lowest possible temperature at which this shape-memory polymer can be additively processed using 3D printing. The print bed speed was set to 10 mm / s. To achieve a high temperature gradient for rapid cooling of the polymer strands extruded from the nozzle, the print bed temperature was varied between 0°C, 50°C, and 90°C. These temperatures were all below the glass transition temperature range of the soft segments, which is approximately 95°C to 125°C (see the...). Fig. 11 ) or the switching temperature of approximately 120.8°C (see the Fig. 13 ) lay.

[0056] In the Figs. 15 and 16(The images above are photographic views of test specimens printed in the above manner and programmed in situ into a temporary form.

[0057] To trigger the shape memory effect, these test specimens were then heated to approximately 140°C for 15 minutes, i.e., to about 19°C above the switching temperature (see the Fig. 13 ), heated, whereupon a shape return of the polymer molded parts by more than 50% of their initial dimensions was observed (see the Figs. 15 and 16 , the lower images in each case). The mold return was similarly pronounced at the selected print bed temperatures of 0°C, 50°C, and 90°C, so further views are unnecessary.

Claims

1. Thermoplastic polymer with shape memory properties, comprising: (a) hard segments, which contain polyurethane units obtained by polyaddition of the isocyanate groups of at least one diisocyanate with the hydroxyl groups of at least one di-, tri- and / or polyol serving as a chain extender to form urethane groups, and / or polyurea units obtained by polyaddition of the isocyanate groups of at least one diisocyanate with the amino groups of at least one di-, tri- and / or polyamine serving as a chain extender to form urea derivative groups; (b) soft segments, which contain polyether units, wherein the polyether units are linked to the hard segments by polyaddition of corresponding polyether diols, triols and / or polyols with the isocyanate groups of the at least one diisocyanate to form urethane groups.and / or - polycarbonate units, wherein the polycarbonate units are linked to the isocyanate groups of the hard segments by polyaddition of corresponding polycarbonate diols to form urethane groups, wherein the proportion of hard segments of the thermoplastic polymer with shape memory properties is at least 50 wt%, wherein at least one - di-, tri- and / or polyol and / or - di-, tri- and / or polyamine of the hard segments serving as a chain extender is formed from a cyclic, heterocyclic and / or aromatic compound, and wherein the switching temperature of the thermoplastic polymer with shape memory properties is at least 90°C.

2. Thermoplastic polymer with shape memory properties according to claim 1, characterized by the fact thatthe proportion of hard segments is at least 60% by mass, in particular at least 70% by mass, preferably at least 80% by mass, and / or at most 98.5% by mass, in particular at most 97.5% by mass, preferably at most 96.5% by mass.

3. Thermoplastic polymer with shape memory properties according to claim 1 or 2, characterized by the fact that(a) at least one di-, tri- and / or polyol serving as a chain extender from the group of: - the dianhydrohexitols, in particular from the group of isosorbide (1,4:3,6-dianhydro-D-sorbitol), isomannide (1,4:3,6-dianhydro-D-mannitol) and isoidide (1,4:3,6-dianhydro-L-iditol), - the dihydroxybenzenes, such as 1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol) and 1,4-dihydroxybenzene (hydroquinone), - the trihydroxybenzenes, such as 1,3,5-trihydroxybenzene (phloroglucinol), 1,2,4-trihydroxybenzene (hydroxyhydroquinone) and 1,2,3-trihydrobenzene (pyrogallol), - the aliphatic cyclic diols, in particular with at least one C5- and / or C6 ring, preferably from the group consisting of cis-1,2-cyclohexanediol, trans-1,2-cyclohexanediol, cis-1,3-cyclohexanediol, trans-1,3-cyclohexanediol, cis-1,4-cyclohexanediol, trans-1,4-cyclohexanediol, cis-1,2-cyclopentanediol, trans-1,2-cyclopentanediol, cis-1,3-cyclopentanediol, trans-1,3-cyclopentanediol and 1,3-cyclopent-4-enediol,- tetrahydrofuran-based heterocyclic diols, in particular tetrahydrofuran-2,5-dimethanol and tetrahydrofuran-2,5-diethanol, - di- and trihydroxybenzoic acids, in particular 3,4,5-trihydroxybenzoic acid (gallic acid), - aromatic di-, tri- and polyols with at least two benzene rings, in particular 3,3',4',5,7-pentahydroxyflavone (quercetin), - polyphenols with at least two hydroxy groups, in particular trans-3,5,4'-trihydroxystilbene (resveratrol), - catechins with at least two hydroxy groups, and - alkylamine- or alkanolamine-substituted dihydroxybenzenes, in particular from the group 4-(2-aminoethyl)benzene-1,2-diol (dopamine) and (R)-3,4-dihydroxyphenylethanolamine (noradrenaline), and / or (b) at least one chain extender serving di-, tri- and / or polyamine of the hard segments from the group - of diaminobenzenes, such as 1,2-diaminobenzene (o-phenylenediamine), 1,3-diaminobenzene (m-phenylenediamine) and 1,4-diaminobenzene (m-phenylenediamine),- triaminobenzenes, such as 1,3,5-triaminobenzene, 1,2,4-triaminobenzene and 1,2,3-triaminobenzene, - aliphatic cyclic diamines, in particular with at least one C5 and / or C6 ring, preferably from the group consisting of 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 2,4-diaminocyclohexane, 2,6-diamino-1-methylcyclohexane, 1,3-diaminomethylcyclohexane, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 4,4'-diaminodicyclohexylmethane, 3,3"-dimethyl-4,4'-diaminodicyclohexylmethane and 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), - tetrahydrofuran-based heterocyclic diamines, in particular 2,5-Furandimethanamine (2,5-bis(aminomethyl)furan), 2,5-furandiethanamine (2,5-bis(aminoethyl)furan) and [2-amino-1-(furan-2-yl)ethyl]dimethylamine, and - the nitrogen-based heterocyclic diamine compounds, in particular from the group consisting of porphyrin (porphine) and 7,8-dihydroporphyrin (chlorine), including mixtures thereof.

4. Thermoplastic polymer with shape memory properties according to one of claims 1 to 3, characterized by the fact that the diisocyanate of the hard segments - is formed from a cyclic, heterocyclic and / or aromatic compound; and / or - from the group of methylenediphenyl diisocyanates (MDI), in particular from the group of diphenylmethane-2,2'-diisocyanate (2,2'-MDI), diphenylmethane-2,4'-diisocyanate (2,4'-MDI), diphenylmethane-4,4'-diisocyanate (4,4'-MDI) including their isomers and isomer mixtures, isophorone diisocyanate (IPDI), 4,4'-diisocyanatodicyclohexylmethane (H 12 MDI), isomers or isomer mixtures of toluene diisocyanates (TDI) or mixtures thereof, is selected.

5. Thermoplastic polymer with shape memory properties according to one of claims 1 to 4, characterized by the fact that(a) the hard segments have an average molar mass of at least 550 g / mol, in particular at least 750 g / mol, preferably at least 1000 g / mol, and / or (b) the entire molecule of the thermoplastic polymer with shape memory properties has an average molar mass of at least 650 g / mol, in particular at least 1000 g / mol, preferably at least 2000 g / mol, and / or at most 500000 g / mol, in particular at most 350000 g / mol, preferably at most 200000 g / mol.

6. Thermoplastic polymer with shape memory properties according to one of claims 1 to 5, characterized by the fact that (a) the polyether units of the soft segments contain polyalkylene glycol units, in particular from the group of polyethylene (PEG), polypropylene (PPG) and polybutylene glycol units (PBG), and / or polytetrahydrofuran (PTHF) units, and / or (b) the polycarbonate units of the soft segments contain polyalkylene carbonate units, such as poly(hexamethylene carbonate) units (PHC).

7. Thermoplastic polymer with shape memory properties according to one of claims 1 to 6, characterized by the fact that the soft segments have an average molar mass of - at least 100 g / mol, in particular at least 150 g / mol, preferably at least 200 g / mol, and / or - at most 10000 g / mol, in particular at most 5000 g / mol, preferably at most 3000 g / mol.

8. Thermoplastic polymer with shape memory properties according to any one of claims 1 to 7, characterized by the fact that it has a switching temperature of at least 100°C, in particular at least 110°C, preferably at least 120°C; and / or a thermal resistance of at least 200°C, in particular at least 220°C, preferably at least 240°C.

9. Polymer molded part, which contains or is entirely formed from at least one thermoplastic polymer with shape memory properties according to any one of claims 1 to 8 or a polymer blend with at least one such polymer, wherein the switching temperature is at least 90°C.

10. A method for producing a polymer molded part according to claim 9, which contains or is entirely formed from at least one thermoplastic polymer with shape memory properties according to any one of claims 1 to 8 or a polymer blend with at least one such polymer, in that the at least one thermoplastic polymer with shape memory properties is plasticized in a plasticizing unit and formed into the polymer molded part in at least one and / or downstream of at least one exit nozzle of the plasticizing unit, wherein the at least one thermoplastic polymer with shape memory properties is heated both in the plasticizing unit and in the at least one exit nozzle to a maximum temperature below the upper limit temperature of the melting transition temperature range of its hard segments, so that the hard segments are not completely melted.where the at least one plasticized thermoplastic polymer with shape memory properties is dispensed from the at least one outlet nozzle of the plasticizing unit, formed into the polymer molded part and cooled to a temperature below the switching temperature in order to program the at least one thermoplastic polymer with shape memory properties together with the production of the polymer molded part in a temporary mold state.

11. Method according to claim 10, characterized by the fact thatthe at least one thermoplastic polymer with shape memory properties is heated in both the plasticizing unit and the at least one exit nozzle to a maximum temperature which corresponds at most to a temperature peak of the melt transition temperature range of its hard segments in a DSC thermogram obtained by means of differential scanning calorimetry (DSC) during heating, wherein the at least one thermoplastic polymer with shape memory properties is heated in both the plasticizing unit and the at least one exit nozzle in particular to a maximum temperature which is below the lower limit temperature of the melt transition temperature range of its hard segments.

12. Method according to claim 10 or 11, characterized by the fact thatthe at least one outlet nozzle of the plasticizing unit is moved during the dispensing of the at least one plasticized thermoplastic polymer with shape memory properties at a speed of at least 1 mm / s, in particular at least 2 mm / s, preferably at least 5 mm / s; and / or at most 80 mm / s, in particular at most 60 mm / s, preferably at most 40 mm / s.

13. Method according to any one of claims 10 to 12, characterized by the fact that that at least one thermoplastic polymer with shape memory properties is held and deformed at a temperature in the range of or above the switching temperature during and / or after its dispensing from the at least one exit nozzle of the plasticizing unit in order to additionally program it in a temporary shape state under the influence of mechanical forces or stresses, after which it is cooled to a temperature below the switching temperature.

14. Method according to any one of claims 10 to 13, characterized by the fact that The programmed shape recovery capacity of the at least one thermoplastic polymer with shape memory properties is set by controlling at least one parameter from the group consisting of: - temperature set in the plasticizing unit, - temperature of the at least one outlet nozzle of the plasticizing unit, - speed of the at least one outlet nozzle during the dispensing of the at least one thermoplastic polymer with shape memory properties, - temperature gradient during the cooling of the at least one thermoplastic polymer with shape memory properties, - pressure set inside the plasticizing unit, - type and / or quantity of heat radiation absorbing and / or thermally conductive additives added to the at least one thermoplastic polymer with shape memory properties.

15. Method according to any one of claims 10 to 14, characterized by the fact thatthat at least one thermoplastic polymer with shape memory properties is plasticized in a plasticizing unit of a 3D printer, is ejected from the plasticizing unit by means of at least one exit nozzle in the form of a print head of the 3D printer which is controlled to be relatively movable with respect to a print bed and is deposited layer by layer to form the polymer molded part, after which the strands of plastic material ejected layer by layer by means of the exit nozzle(s) of the print head are cooled to a temperature below the switching temperature.

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